10558236

Direct Digital Synthesis Systems and Methods

PublishedFebruary 11, 2020
Assigneenot available in USPTO data we have
Technical Abstract

Patent Claims
20 claims

Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.

Claim 1

Original Legal Text

1. A digital to analog converter (DAC) comprising: a decoder coupled to an input of the DAC; a PMOS DAC coupled between the decoder and an output of the DAC; an NMOS DAC coupled between the decoder and the output of the DAC; a switch coupled between outputs of the PMOS DAC and the NMOS DAC and the output of the DAC and configured to select the output of the PMOS DAC or the output of the NMOS DAC as the output of the DAC based, at least in part, on a control signal provided to the switch by the decoder; and bias circuitry configured to bias the PMOS DAC and the NMOS DAC according to one or more desired bias voltages.

Plain English Translation

A digital-to-analog converter (DAC) is designed to convert digital signals into analog outputs with improved performance and flexibility. Traditional DACs often suffer from limitations in linearity, power efficiency, and dynamic range, particularly when operating under varying conditions. This DAC addresses these issues by incorporating both PMOS and NMOS DAC segments, each coupled to a shared decoder that processes the input digital signal. The PMOS DAC and NMOS DAC are independently biased using dedicated bias circuitry, allowing for precise control of their operating conditions. A switch selectively routes the output of either the PMOS DAC or the NMOS DAC to the final output based on a control signal from the decoder. This configuration enables dynamic adjustment of the DAC's performance characteristics, such as output range and linearity, by leveraging the complementary strengths of PMOS and NMOS transistors. The bias circuitry ensures optimal operation of both DAC segments, further enhancing accuracy and efficiency. This design improves the DAC's adaptability to different operating environments while maintaining high precision and low power consumption.

Claim 2

Original Legal Text

2. The DAC of claim 1 , wherein: the PMOS DAC comprises a plurality of PMOS transistors controlled by the decoder; the NMOS DAC comprises a plurality of NMOS transistors controlled by the decoder; and the plurality of PMOS transistors and the plurality of NMOS transistors are arranged to form at least respective portions of a differential current steering DAC.

Plain English Translation

A digital-to-analog converter (DAC) system addresses the need for precise current steering in integrated circuits, particularly in applications requiring high linearity and low power consumption. The system includes a PMOS DAC and an NMOS DAC, each comprising multiple transistors controlled by a decoder. The PMOS transistors and NMOS transistors are arranged to form at least portions of a differential current steering DAC, enabling complementary current paths for improved performance. The decoder selectively activates the transistors to steer current between the PMOS and NMOS branches, allowing fine-grained control over the output current. This configuration enhances linearity and reduces distortion by balancing current flow between the two transistor types. The differential arrangement further improves noise immunity and power efficiency, making the DAC suitable for high-precision applications such as communication systems, signal processing, and sensor interfaces. The system leverages complementary transistor operation to achieve accurate current steering while minimizing power dissipation and maintaining high signal integrity.

Claim 3

Original Legal Text

3. The DAC of claim 2 , wherein: the plurality of PMOS transistors and the plurality of NMOS transistors each comprise at least 128 transistors; and the DAC is configured to implement at least an 8-bit DAC.

Plain English Translation

A digital-to-analog converter (DAC) is designed to convert digital signals into analog outputs with high precision. The DAC includes a plurality of PMOS transistors and a plurality of NMOS transistors, each comprising at least 128 transistors. These transistors are configured to generate an analog output signal based on digital input signals. The DAC is capable of implementing at least an 8-bit resolution, meaning it can produce 256 distinct output levels. The use of a large number of transistors ensures fine-grained control over the analog output, reducing quantization errors and improving accuracy. The DAC may be used in applications requiring high-resolution signal conversion, such as audio processing, communication systems, and instrumentation. The design leverages both PMOS and NMOS transistors to enhance performance, stability, and power efficiency. The configuration allows for precise current or voltage scaling, ensuring accurate analog signal representation from digital inputs.

Claim 4

Original Legal Text

4. The DAC of claim 2 , wherein: the decoder is configured to provide a most significant bit of a digital signal provided to the decoder as the control signal provided to the switch; and the switch is configured to select an output of the PMOS DAC or the NMOS DAC to generate a corresponding negative or positive portion of an analog signal provided by the output of the DAC.

Plain English Translation

This invention relates to digital-to-analog converters (DACs) and addresses the challenge of efficiently generating both positive and negative analog signal portions from a digital input. The system includes a decoder that receives a digital signal and extracts the most significant bit (MSB) to serve as a control signal. This control signal directs a switch to select between outputs from a PMOS-based DAC and an NMOS-based DAC. The PMOS DAC generates a positive analog signal portion, while the NMOS DAC generates a negative analog signal portion. The switch routes the appropriate output based on the MSB, ensuring the analog signal accurately reflects the digital input's polarity. This design improves efficiency by leveraging complementary DAC structures and simplifies control logic by using the MSB as the selection criterion. The system is particularly useful in applications requiring precise analog signal generation with minimal hardware complexity.

Claim 5

Original Legal Text

5. The DAC of claim 1 , wherein: the PMOS DAC comprises a PMOS DAC common bias coupled to a high rail reference through a variable PMOS DAC current source; the NMOS DAC comprises an NMOS DAC common bias coupled to a low rail reference through a variable NMOS DAC current source; and the bias circuitry comprises: an internal PMOS DAC reference rail coupled to the PMOS DAC and configured to bias the PMOS DAC by the voltage difference between the PMOS DAC common bias and the internal PMOS DAC reference rail; and an internal NMOS DAC reference rail coupled to the NMOS DAC and configured to bias the NMOS DAC by the voltage difference between the NMOS DAC common bias and the internal NMOS DAC reference rail.

Plain English Translation

This invention relates to digital-to-analog converter (DAC) circuitry, specifically addressing the challenge of maintaining precise current control in both PMOS and NMOS DACs while minimizing power consumption and reference voltage dependencies. The invention describes a dual-DAC architecture featuring independent bias control for PMOS and NMOS DAC segments. The PMOS DAC includes a common bias node connected to a high rail reference through a variable current source, allowing dynamic adjustment of the PMOS DAC's operating current. Similarly, the NMOS DAC has a common bias node linked to a low rail reference through another variable current source, enabling independent current control for the NMOS DAC. The bias circuitry further incorporates internal reference rails for each DAC type. The internal PMOS DAC reference rail biases the PMOS DAC by the voltage difference between the PMOS common bias and the internal reference, while the internal NMOS DAC reference rail biases the NMOS DAC using the voltage difference between the NMOS common bias and its internal reference. This design ensures precise current matching between the PMOS and NMOS DACs while reducing sensitivity to supply voltage variations. The variable current sources allow dynamic current scaling, improving power efficiency and performance across different operating conditions. The internal reference rails provide stable bias points, enhancing linearity and reducing distortion in the DAC output.

Claim 6

Original Legal Text

6. The DAC of claim 5 , wherein: the internal PMOS DAC reference rail is coupled to the low rail reference; and the internal NMOS DAC reference rail is coupled to the high rail reference.

Plain English Translation

This invention relates to digital-to-analog converter (DAC) circuitry, specifically addressing the challenge of efficiently managing reference voltage rails in integrated circuits. The invention describes a DAC architecture where the internal PMOS DAC reference rail is directly connected to the low rail reference, while the internal NMOS DAC reference rail is connected to the high rail reference. This configuration optimizes voltage distribution within the DAC, reducing power consumption and improving signal integrity by minimizing voltage drops across internal reference paths. The DAC includes both PMOS and NMOS transistors, with the PMOS transistors receiving their reference voltage from the low rail and the NMOS transistors receiving theirs from the high rail. This arrangement ensures that each transistor type operates within its optimal voltage range, enhancing performance and reliability. The invention is particularly useful in low-power applications where efficient voltage management is critical, such as in portable electronics or energy-efficient integrated circuits. By decoupling the reference rails for PMOS and NMOS transistors, the DAC achieves better thermal stability and reduced noise interference, leading to more accurate analog output signals. The overall design simplifies the reference voltage distribution network, reducing complexity and cost while maintaining high precision in analog conversions.

Claim 7

Original Legal Text

7. The DAC of claim 1 , wherein: the PMOS DAC comprises a PMOS DAC common bias coupled to a high rail reference through a variable PMOS DAC current source; the NMOS DAC comprises an NMOS DAC common bias coupled to a low rail reference through a variable NMOS DAC current source; the bias circuitry comprises first and second variable current sources coupled in series between the high rail reference and the low rail reference and configured to generate a common bias therebetween; and the variable PMOS DAC current source is linked to and controlled by the first variable current source via a first bias control reference and the variable NMOS DAC current source is linked to and controlled by the second variable current source via a second bias control reference.

Plain English Translation

This invention relates to a digital-to-analog converter (DAC) system with improved bias control for PMOS and NMOS DACs. The system addresses the challenge of maintaining precise current matching and stability in DACs by dynamically adjusting bias currents to compensate for variations in operating conditions. The DAC system includes a PMOS DAC and an NMOS DAC, each with a dedicated current source. The PMOS DAC is coupled to a high rail reference through a variable PMOS DAC current source, while the NMOS DAC is coupled to a low rail reference through a variable NMOS DAC current source. Bias circuitry generates a common bias between the high and low rail references using first and second variable current sources connected in series. The PMOS DAC current source is controlled by the first variable current source via a first bias control reference, and the NMOS DAC current source is controlled by the second variable current source via a second bias control reference. This linked control ensures that the DAC currents are dynamically adjusted to maintain consistent performance across different operating conditions, improving accuracy and stability in analog signal conversion. The system is particularly useful in applications requiring high-precision DAC performance, such as communication systems, measurement instruments, and signal processing circuits.

Claim 8

Original Legal Text

8. The DAC of claim 7 , further comprising: a first feedback element coupled between the common bias generated between the first and second variable current sources, the PMOS DAC common bias, and the first bias control reference; and a second feedback element coupled between the common bias, the NMOS DAC common bias, and the second bias control reference; wherein the first and second feedback elements are configured to compensate for drift or voltage differences between the common bias and the respective DAC common biases by adjusting respective first and second bias control references.

Plain English Translation

This invention relates to digital-to-analog converters (DACs) and addresses the problem of drift or voltage differences between bias voltages in PMOS and NMOS DACs, which can degrade performance. The system includes a DAC with first and second variable current sources that generate a common bias voltage. The DAC also has separate PMOS and NMOS DAC common bias voltages. To compensate for drift or voltage differences between the common bias and the DAC-specific biases, the system includes first and second feedback elements. The first feedback element connects the common bias to the PMOS DAC common bias and a first bias control reference, while the second feedback element connects the common bias to the NMOS DAC common bias and a second bias control reference. These feedback elements adjust the bias control references to maintain consistent bias conditions, improving DAC stability and accuracy. The solution ensures that variations in bias voltages are dynamically corrected, enhancing the reliability of the DAC output.

Claim 9

Original Legal Text

9. The DAC of claim 8 , wherein: the first and second feedback elements comprise differential amplifiers with outputs coupled to the respective first bias control references.

Plain English Translation

Technical Summary: This invention relates to digital-to-analog converters (DACs) with improved feedback control for bias voltage regulation. The problem addressed is maintaining stable and accurate analog output signals in DACs by dynamically adjusting bias voltages in response to operating conditions. The DAC includes a first feedback element and a second feedback element, each comprising a differential amplifier. The differential amplifiers monitor and regulate bias control references for different sections of the DAC. The outputs of these amplifiers are coupled to respective bias control references, allowing real-time adjustments to maintain optimal performance. This feedback mechanism ensures precise control over the DAC's analog output, compensating for variations in temperature, supply voltage, or process variations. The differential amplifiers provide high-gain feedback, enabling fine-tuned regulation of bias voltages. By coupling their outputs directly to the bias control references, the system achieves rapid response to changes, improving linearity and reducing distortion in the DAC's output. This design is particularly useful in high-precision applications where stable analog signals are critical, such as in communication systems, instrumentation, and signal processing. The invention enhances DAC performance by integrating active feedback control, ensuring consistent and accurate analog outputs under varying conditions. The use of differential amplifiers for feedback provides robustness and precision, addressing common challenges in DAC design.

Claim 10

Original Legal Text

10. The DAC of claim 1 , further comprising: a bias regulator configured to select, regulate, or otherwise control an internal PMOS DAC reference rail for the PMOS DAC and/or an internal NMOS DAC reference rail for the NMOS DAC.

Plain English Translation

This invention relates to digital-to-analog converters (DACs) and addresses the challenge of managing reference voltage rails in DAC circuits to improve performance and efficiency. The invention describes a DAC system that includes both PMOS (p-channel metal-oxide-semiconductor) and NMOS (n-channel metal-oxide-semiconductor) DACs, each requiring stable reference voltage rails for accurate signal conversion. The system incorporates a bias regulator that dynamically selects, regulates, or controls the internal reference rails for both the PMOS and NMOS DACs. This regulation ensures that the reference voltages remain stable and optimized for the DACs' operation, reducing noise, improving linearity, and enhancing overall conversion accuracy. The bias regulator can adjust the reference rails based on operating conditions, such as temperature or load variations, to maintain consistent performance. By integrating this regulation mechanism, the DAC system achieves better precision and reliability in analog signal generation. The invention is particularly useful in applications requiring high-performance DACs, such as communication systems, instrumentation, and precision measurement devices.

Claim 11

Original Legal Text

11. The DAC of claim 1 , further comprising: an output filter coupled between the switch and the output of the DAC and configured to filter an output analog signal of the DAC according to a desired pass band.

Plain English Translation

This invention relates to digital-to-analog converters (DACs) and addresses the challenge of improving signal quality in analog output. The DAC includes a switch that controls the conversion process and an output filter connected between the switch and the DAC output. The filter is designed to refine the analog signal by removing unwanted frequency components, ensuring the output adheres to a specified pass band. This enhances signal integrity by suppressing noise and distortion outside the desired frequency range. The filter's configuration allows for precise control over the analog signal's frequency characteristics, making it suitable for applications requiring high-fidelity signal conversion, such as audio processing, telecommunications, and instrumentation. By integrating the filter directly into the DAC architecture, the invention simplifies system design and reduces the need for external filtering components, improving efficiency and performance. The solution is particularly valuable in systems where signal purity and bandwidth management are critical.

Claim 12

Original Legal Text

12. A digital synthesizer comprising the DAC of claim 1 , wherein: the digital synthesizer comprises a multichannel digital synthesizer comprising a plurality of channels; and each one of the plurality of channels of the multichannel digital synthesizer comprises one DAC according to claim 1 .

Plain English Translation

A digital synthesizer includes a multichannel architecture with multiple independent channels, each equipped with a dedicated digital-to-analog converter (DAC). The DAC in each channel converts digital audio signals into analog outputs, enabling precise and independent control over multiple audio channels. This design allows for complex sound generation and processing, such as polyphonic synthesis, multi-timbral playback, or spatial audio effects, by providing separate signal paths for each channel. The multichannel structure enhances flexibility in sound design, allowing for simultaneous playback of different waveforms, modulation schemes, or effects across channels. The DACs in each channel may incorporate features like noise shaping, dynamic range optimization, or sample rate conversion to improve audio quality. This approach is particularly useful in electronic music production, sound synthesis, and audio processing applications where multiple independent sound sources or effects are required. The system enables efficient signal routing and processing, reducing latency and improving synchronization between channels.

Claim 13

Original Legal Text

13. A system comprising the DAC of claim 1 , the system further comprising: a driver, wherein the output of the DAC is coupled to an input of the driver; and a programmable logic device (PLD) coupled to an input of the DAC; wherein the PLD is configured to provide a digital signal to the DAC and the DAC is configured to convert the digital signal to a corresponding analog signal and provide the corresponding analog signal to the input of the driver.

Plain English Translation

This system relates to digital-to-analog conversion (DAC) and signal processing, addressing the need for precise analog signal generation from digital inputs in applications requiring programmable control. The system includes a digital-to-analog converter (DAC) that receives a digital signal from a programmable logic device (PLD) and converts it into a corresponding analog signal. The analog output of the DAC is then provided to a driver, which amplifies or conditions the signal for further use. The PLD generates the digital signal based on programmable instructions, allowing flexible control over the analog output. The DAC converts the digital input into an analog voltage or current with high precision, ensuring accurate signal representation. The driver amplifies the analog signal to meet the requirements of downstream components, such as sensors, actuators, or communication interfaces. This system enables dynamic adjustment of analog signals in real-time, making it suitable for applications in industrial automation, telecommunications, and test and measurement equipment. The integration of the PLD, DAC, and driver in a single system simplifies signal processing workflows while maintaining high performance and programmability.

Claim 14

Original Legal Text

14. The system of claim 13 , wherein: the driver is configured to generate an output driver signal based on the corresponding analog signal provided by the DAC and provide the output driver signal to a sensor system; and the PLD is configured to receive sensor signals from the sensor system, corresponding to the output driver signal, and process the sensor signals to measure and/or detect an event sensed by the sensor system.

Plain English Translation

This invention relates to a system for driving and processing signals in a sensor system, particularly for measuring or detecting events. The system includes a programmable logic device (PLD) and a driver circuit. The PLD generates digital control signals and provides them to a digital-to-analog converter (DAC), which converts the digital signals into corresponding analog signals. The driver circuit receives these analog signals and generates an output driver signal to stimulate a sensor system. The sensor system, in response to the driver signal, produces sensor signals that are fed back to the PLD. The PLD processes these sensor signals to measure or detect events sensed by the system. The system may include multiple DACs and drivers, each associated with a specific sensor channel, allowing for parallel signal generation and processing. The PLD can also adjust the digital control signals based on the processed sensor signals to optimize the measurement or detection process. This configuration enables precise control and analysis of sensor data, improving accuracy and reliability in applications such as environmental monitoring, industrial sensing, or biomedical measurements.

Claim 15

Original Legal Text

15. The system of claim 13 , wherein: the PLD is configured to control one or more variable current sources of the bias circuitry to adjust respective bias voltages across the PMOS DAC and/or the NMOS DAC.

Plain English Translation

This invention relates to a system for controlling bias voltages in a digital-to-analog converter (DAC) using a programmable logic device (PLD). The system addresses the challenge of dynamically adjusting bias voltages in PMOS and NMOS DACs to optimize performance, such as linearity, power efficiency, or speed, under varying operating conditions. The system includes bias circuitry with one or more variable current sources, which are controlled by the PLD to adjust bias voltages across the PMOS DAC and/or the NMOS DAC. The PLD configures the current sources to modify the bias voltages, enabling precise tuning of the DAC's electrical characteristics. This allows the system to adapt to different operational requirements, such as temperature variations, supply voltage changes, or varying signal conditions, ensuring consistent performance. The bias circuitry may include multiple current sources, each adjustable independently or in combination to fine-tune the bias voltages. The PLD dynamically adjusts these current sources based on predefined settings, real-time feedback, or external control signals, providing flexibility in optimizing the DAC's behavior. This approach enhances the DAC's versatility and reliability in applications requiring precise analog signal conversion, such as communication systems, measurement instruments, or power management circuits.

Claim 16

Original Legal Text

16. A method for fabricating a digital to analog converter (DAC) for a digital synthesizer in an integrated circuit, the method comprising: forming, on a substrate of the integrated circuit, a decoder coupled to an input of the DAC; forming a PMOS DAC coupled between the decoder and an output of the DAC; forming an NMOS DAC coupled between the decoder and the output of the DAC; forming a switch coupled between outputs of the PMOS DAC and the NMOS DAC and the output of the DAC and configured to select the output of the PMOS DAC or the output of the NMOS DAC as the output of the DAC based, at least in part, on a control signal provided to the switch by the decoder; and forming bias circuitry configured to bias the PMOS DAC and the NMOS DAC according to one or more desired bias voltages.

Plain English Translation

This invention relates to the fabrication of a digital-to-analog converter (DAC) for a digital synthesizer in an integrated circuit. The DAC converts digital signals into analog signals, which is essential for generating audio waveforms in synthesizers. A common challenge in DAC design is achieving high precision and linearity while minimizing power consumption and circuit complexity. The method involves forming a decoder on a substrate of the integrated circuit, which is coupled to the input of the DAC. The decoder processes digital input signals and controls the operation of the DAC. A PMOS DAC and an NMOS DAC are formed and connected between the decoder and the DAC output. These DACs use complementary PMOS and NMOS transistors to generate analog signals from digital inputs. A switch is formed between the outputs of the PMOS and NMOS DACs and the DAC output. The switch selects either the PMOS or NMOS DAC output based on a control signal from the decoder, allowing for flexible signal routing and improved performance. Bias circuitry is also formed to provide the necessary bias voltages to the PMOS and NMOS DACs, ensuring stable and accurate operation. This design enhances signal quality and efficiency in digital synthesizer applications.

Claim 17

Original Legal Text

17. The method of claim 16 , wherein: the PMOS DAC comprises a PMOS DAC common bias coupled to a high rail reference through a variable PMOS DAC current source; the NMOS DAC comprises an NMOS DAC common bias coupled to a low rail reference through a variable NMOS DAC current source; the bias circuitry comprises first and second variable current sources coupled in series between the high rail reference and the low rail reference and configured to generate a common bias therebetween; and the variable PMOS DAC current source is linked to and controlled by the first variable current source via a first bias control reference and the variable NMOS DAC current source is linked to and controlled by the second variable current source via a second bias control reference.

Plain English Translation

This invention relates to digital-to-analog converter (DAC) circuitry, specifically addressing the challenge of maintaining precise current matching and bias stability in complementary metal-oxide-semiconductor (CMOS) DACs. The system includes a PMOS DAC and an NMOS DAC, each with a dedicated current source. The PMOS DAC is coupled to a high rail reference through a variable PMOS DAC current source, while the NMOS DAC is coupled to a low rail reference through a variable NMOS DAC current source. Bias circuitry generates a common bias between the high and low rail references using first and second variable current sources connected in series. The PMOS DAC current source is controlled by the first variable current source via a first bias control reference, and the NMOS DAC current source is controlled by the second variable current source via a second bias control reference. This configuration ensures consistent current distribution and bias stability across the DACs, improving accuracy and performance in analog signal conversion. The variable current sources allow dynamic adjustment of the bias points, enabling adaptive operation under varying conditions. The system is particularly useful in applications requiring high-precision analog outputs, such as communication systems, measurement instruments, and signal processing circuits.

Claim 18

Original Legal Text

18. The method of claim 17 , further comprising: forming a first feedback element coupled between the common bias generated between the first and second variable current sources, the PMOS DAC common bias, and the first bias control reference; and forming a second feedback element coupled between the common bias, the NMOS DAC common bias, and the second bias control reference; wherein the first and second feedback elements are configured to compensate for drift or voltage differences between the common bias and the respective DAC common biases by adjusting respective first and second bias control references.

Plain English Translation

This invention relates to digital-to-analog converter (DAC) bias control systems, specifically addressing drift or voltage differences between bias voltages in mixed-signal integrated circuits. The problem solved is maintaining accurate and stable bias voltages in DACs, particularly when using both PMOS and NMOS transistors, to ensure consistent performance despite variations in operating conditions. The method involves generating a common bias voltage shared between first and second variable current sources, which are coupled to PMOS and NMOS DACs, respectively. To compensate for drift or voltage differences between the common bias and the DAC-specific biases, first and second feedback elements are formed. The first feedback element connects the common bias to the PMOS DAC's common bias and a first bias control reference, while the second feedback element connects the common bias to the NMOS DAC's common bias and a second bias control reference. These feedback elements dynamically adjust the bias control references to correct any deviations, ensuring stable operation. The feedback elements may include resistors, capacitors, or active components to provide the necessary compensation. This approach improves DAC linearity and reduces errors caused by environmental or process variations.

Claim 19

Original Legal Text

19. A method for operating a digital to analog converter (DAC) for a digital synthesizer, the method comprising: controlling the DAC to provide an analog signal to an input of a driver, wherein the DAC comprises: a decoder coupled to an input of the DAC; a PMOS DAC coupled between the decoder and an output of the DAC; an NMOS DAC coupled between the decoder and the output of the DAC; a switch coupled between outputs of the PMOS DAC and the NMOS DAC and the output of the DAC and configured to select the output of the PMOS DAC or the output of the NMOS DAC as the output of the DAC based, at least in part, on a control signal provided to the switch by the decoder; and bias circuitry configured to bias the PMOS DAC and the NMOS DAC according to one or more desired bias voltages; and controlling one or more variable current sources of the bias circuitry to adjust respective bias voltages across the PMOS DAC and/or the NMOS DAC.

Plain English Translation

This invention relates to digital-to-analog converters (DACs) for digital synthesizers, addressing the challenge of efficiently generating high-quality analog signals from digital inputs. The method involves operating a DAC that includes both PMOS and NMOS DAC sections, each coupled to a decoder and an output switch. The switch selects either the PMOS or NMOS DAC output based on a control signal from the decoder, allowing flexible signal generation. Bias circuitry adjusts the bias voltages across the PMOS and NMOS DACs using variable current sources, enabling precise control over their operation. This dual-DAC architecture with configurable bias voltages improves signal fidelity and reduces distortion in digital synthesizer applications. The method ensures optimal performance by dynamically adjusting the bias conditions to match desired signal characteristics, enhancing the overall efficiency and accuracy of the DAC in synthesizing analog waveforms.

Claim 20

Original Legal Text

20. The method of claim 17 , further comprising: providing a digital signal to the DAC configured to cause the DAC to generate the analog signal provided to the input of the driver.

Plain English Translation

This invention relates to digital-to-analog conversion (DAC) systems used in signal processing, particularly for generating analog signals from digital inputs. The problem addressed is the need for precise control over analog signal generation in systems where digital signals must be converted to analog form for further processing or transmission. Traditional DACs may introduce distortion or inaccuracies, especially in high-performance applications. The invention describes a method for improving signal integrity in such systems. A digital signal is provided to a DAC, which converts it into an analog signal. This analog signal is then supplied to the input of a driver circuit. The driver amplifies the analog signal to a level suitable for subsequent stages, such as transmission or further amplification. The method ensures that the digital-to-analog conversion process is optimized to minimize noise and distortion, enhancing the overall signal quality. The driver circuit may include additional features, such as impedance matching or filtering, to further refine the analog signal before output. The system is designed to work in applications requiring high-fidelity signal reproduction, such as audio processing, telecommunications, or instrumentation. By carefully controlling the digital input to the DAC and the subsequent amplification by the driver, the invention ensures accurate and reliable analog signal generation.

Patent Metadata

Filing Date

Unknown

Publication Date

February 11, 2020

Inventors

Vinh Ho
Magathi Jayaram Willis
Keith Truong
Hamid Ghezelayagh

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DIRECT DIGITAL SYNTHESIS SYSTEMS AND METHODS